No power lights etc but ignition turns over?

The headlight switch is a multifunction switch.
Power at the B1 terminal is only to feed the headlights
It has a 15 amp breaker.
Power at the B2 terminal feeds the parking and marker lights.
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Internally B2 also connects to the rheostat.
Power out from the rheostat is wired like this
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The wiring for the instrument lights goes to a lower current fuse.
Finally there is a connection for the dome/interior lights. This is a ground connection just like the door switches.
In sum, there are three hot wires connected to the headlight switch.